Rivet remover



N 1940- R. TEMPLE, JR

RIVET REMOVER Filed Nov. 22, 1938 ME BY W 6 '/l-vcb vepw A24 ATTORNEYS laborious operation which, furthermore, often Patented Nov. 12, 1940 UNITED STATES PATENT OFFICE 9Claims.

performed on button-headed rivets by cutting off the head of the rivet or other member with a cold chisel or a saw which is a time-consuming and has the disadvantage of enlarging the hole or bending or distorting the members to which the rivet is secured. As obnoxious as button-head rivets are to remove, this is relatively simple when compared to removing countersunk rivets. These must be burned out with a cutting torch, which often so injures the hole that it must be redrilled and recountersunk.

It is the general object .of my invention to avoid and overcome the foregoing and other objections to known methods and apparatus, as just stated, by the provision of improved means and methods for utilizing the force of a detonated explosive charge to remove a rivet or other headed member from the bodies to which it is secured.

Another object of my invention is the provision of apparatus operated by a blankcartridge or other explosive charge for driving a punch with high force and velocity through the head of a rivet to punch the body or stem portion thereof out of a hole in which it is secured;

Another object of my invention is the provision of explosively actuated apparatus for punching out or removing rivets or similarly headed members and characterized by the inclusion of a shock-absorbing member for cushioning the final punching movement of the apparatus.

Another object of my invention is to provide explosively actuated apparatus for driving a punch or similar member at high velocity into and through a rivet or the like, and which is characterized by being relatively light in weight, long wearing in use, easily operated by the ordinary workman, and which can be rapidly and safely reloaded in a minimum of time to be used over and over again without disassembly for cleaning or repairing.

Another object of my invention is the provision of an improved method for driving a rivet or (01. lei-119) a similar member out of the body in which it is secured by the force of a detonated explosive charge, and which is characterized by relatively simple yet accurate aligning steps.

The foregoing and other objects of my invention are achieved by the provision of an apparatus comprising a barrel, a piston slidably mounted in the barrel, a punch carried by the piston, a piston-retaining means associated with the muzzle end of the barrel and having a central 10 aperture therethrough to permit the passage of the punch. Completing the combination'are resilient shock-absorbing and cushioning means for stopping the movement of the piston, a frangible aligning device carried by the retaining means, and means for detonating an explosive charge behind the piston to drive it and the punch toward the muzzle end of the barrel.

My improved method for removing rivets or the like includes the steps of centering a frangible member with the rivet, aligning the barrel with the frangible member, driving the punch out of the barrel and through the frangible member and rivet by the power of a detonated explosive charge, and cushioning the final movement of the punch in the barrel. One embodiment of my invention is illustrated in the accompanying drawing wherein Fig.

I 1 is a plan view of the apparatus; Fig. 2 is a longitudinal cross-sectional view taken on the line 11-11 of Fig. 1; and Fig. 8 is a trans- .verse cross-sectional view taken on line III-HI 'of Fig. 2.

In the form of my invention specifically illustrated in the drawing the numeral 10 indicates 5 generally a barrel which slidably receives a piston l2. The piston I2 is adapted to removably carry a punch M in axial alignment in the barrel l0, and to this vend the piston I2 is formed with a socket l6 which receives a stud l8 formed 40.

on the end of the punch M. A spring-pressed detent 20 having a compressible rubber plug therein serves to releasably hold the stud l8 in the socket I6 so that punches of different sizes can be used in conjunction with the apparatus, as will be understood.

Means are employed in conjunction with the apparatus for stopping the forward or outward movement of the piston I2 and these means may conveniently take the form of retaining nut 22, which has a threaded connection 24 with the muzzle end of the barrel l0 andj'which is provided with a central aperture 26 of a diameter slightly greater than the largest diameter of the punch l4. Associated with the retaining nut 22 is a shock-absorbing and cushioning unit indicated as a whole by the numeral 28. The shockabsorbing unit 28 is an important part of my apparatus inasmuch as it prevents breakage of any 5 of the parts thereof and is particularly adapted to withstand the relatively heavy blows to the retaining nut 22 by the piston l2 and its associated Darts. g

Specifically, the shock-absorbing unit 28 includes a plurality, such as four, of metal discs marked 30 which are in the nature of flat washerlike members formed with a plurality of radially directed tabs 32. The discs 38 are formed of a metal, such as steel, which has little or no afiim'ty for rubber. In other words, when rubber is vulcanized in contact with the steel surfaces there will be no adhesion between the surface and the rubber. However, the discs 30 are embedded in a cylindrical block of resilient rubber marked 34 which, as clearly shown in Figs. 2 and 3, is of smaller diameter than the over-all diameter of the discs 30, including the tabs 32, but which is of greater diameter than the diameter of the discs without including the tabs 32. Thus the shock-absorbing unit comprises a plurality of steel discs positioned in spaced parallel relation to each other and separated by resilient rubber which is in the form of a. pluralityof separate layers connected by integralstud or finger portions 36. The tabs 32 of the individual discs 30 are not positioned in opposed relation but are staggered circumferentiallyrelative to each other so that the stud or finger portions 36 are scattered more or less uniformly throughout the entire shock-absorbing unit. Terminating the resilient member body at a point radially within the outer periphery of the tabs 32 provides a space into which the rubber body may flow when the shock- 40 absorbing unit is subjected to high axial force, as is the case when the piston is driven against it. The fact that the rubber is not vulcanized to the metal discs permits the flowing displacement of the rubber, asjust described, without any tearing action on the rubber.

I employ a relatively heavy steel washer 40 between the end of the barrel l8 and the shockabsorbing unit 28, which washer functions to uniformly apply the force of the piston over the entire surface of the shock-absorbing unit 28. The retaining nut 22 not only serves to carry the shock-absorbing unit 28, as just described, but also is adapted to carry aligning means which take the form of a frangible metal disc 42 formed with an axially positioned outwardly directed pointed stud 44 which is adapted to be received in a center punched hole in the rivet or other member to be removed. The frangible disc 42 is conveniently connected to the retaining nut 22 by the provision of an integral flange 46 on the disc which fits snugly over a circular flange 48 formed on the end of the retaining nut 22. It should be understood that button-head rivets or the like can be properly aligned with the apparatus without the use of the frangible disc since the curved head of the rivet aligns itself with the round opening in the retaining nut 22. Thus, the center punching and frangible disc need only be used with a countersunk rivet or similar member.

The breech end of the barrel I8 is adapted to removably receive a breech member marked 50, and this may be achieved by the provision of a threaded connection 52 therebetween. A set- 75 screw 54 serves to lock the breech member 58 in place at the breech end of the barrel II. The breech member 58 is formed with an axial chamber 56 adapted to removably receive an explosive charge which is conveniently made in the form of a blank cartridge 58.

Means are preferably provided for holding the piston l2 against movement in the barrel l8 until substantially the greatest energy is developed from the detonated explosive charge. These means may take the form of one or more spring-pressed detents 88 carried by the barrel l 0 and engaging with the outer end of the punch I4. Instead of a metal compression spring I employ a compressible rubber plug in the detent 60 which I have found has increased life and is less subject to breakage. Further, I may form the breech member 50 with a tapered extension 62 which extends into a skirt 64 formed on the piston 12 and having a complementary taper. The tapers between the extension 82 and the piston skirt 64 are at a relatively small angle to the axis of the barrel, and there is a definite wedging action between these parts. While I preferably employ both the wedging action just described and the spring-pressed detents 60 for holding the piston l2 against movement, it should be understood that either of the stated means could be used alone and that furthermore at least certain of the advantages of my invention are retained even when both retarding means are eliminated.

Inorder to relieve the pressure of the expanded gases of the detonated explosive charge once the piston l2 has moved to perform the desired work, I preferably incorporate one or more bleeder vents 66 between the inside of the skirt 64 on the piston and the outer circumference of the piston. I also provide a slightly enlarged bore 10 at the muzzle end of the barrel III, which cooperates with the vent or vents 66 when the piston I2 is at the most outward movement of its travel to thereby exhaust the gases behind the piston to the front end of the piston and eventually to the atmosphere with a comparatively slow bleeding action. Further, I preferably provide circumferential grooves '12 on the piston l2 or on its skirts, which grooves are adapted to receive a suitable lubricant which can be introduced into the barrel through a pressure gun fitting 14.

The breech member 50 is preferably formed integral with a stock 88,.usually made of a substantially cylindrical shape in cross section, and to which is secured a handle 82 as by cap screws 84. The stock 88 is provided with a transverse opening 86 which is substantially rectangular in cross section and which slidably receives a breech-block 88 for limited lateral movement, as controlled, for example, by a screw 90 carried in the stock and having an end extending into a relatively short groove 82 formed in the side face of the breech-block 88. The breech-block 88 carries a firing pin 94 so that in one lateral position of the breech-block 88 the firing pin 84 is in alignment with the blank cartridge 58 carried in the chamber 56 of the breech member 50. In the other lateral position of the breech-block 88 the firing pin 94 is moved out of alignment with the blank cartridge 58 to permit the ejecting of the detonated shell and the introduction of a new cartridge into the breech member.

The ejecting of the tired cartridge shell is effected by the lateral movement of the breechblock 88. Specifically, an ejector finger in the form of a triangular plate 96 is received in a suitable slot 91 and is pivotally mounted near its center on a pin 98 carried by the breech member 58. The one end of the finger plate 96 is formed withan extension I88 which is slidably received in a. slot I82 cut in the opposed face of the-breech-block 88. The length of the slot I82 is such that'when the breech-block 88 is near the end of its travel to expose the breech chamber the end of the slot I82 engages with the extension I88 on the finger plate 96 to tilt the plate about the pivot pin 98 and eject the blank cartridge 58. It will be seen from Fig. 1 that the finger plate 96 is positioned ofi center of the breech chamber 56 so that the end of the finger plate 96 remote from the extension I88 engages behind the flange on the blank cartridge 58, as will be understood.

A spring-pressed ball detent I84 serves to lock the breech-block 88 in either the firing or'loading position. To facilitate the loading operation and to provide the necessary strength while reducing the lateral travel of the breech-block 88 to a minimum, its one end is formed with a U-shaped opening or slot marked I86 which is sufliciently wide to receive a blank cartridge;

The firing pin 94 is adapted to be held by suitable means in a retarded or non-operating posi-.

tion, and to this end the firing pin is formed or provided with a flange I I8 which is received slidably in an enlarged aperture formed in the breech-block 88. A coiled compression-spring II2 carried in the enlarged bore engages with the flange I I8 and forces the firing pin against a retaining collar 4 which is locked in threaded relation with the breech-block 88. The stock portion 88 of the apparatus is formed with an axial bore I28 which slidably receives a hammer I22. The hammer I22 is in turn provided with an axial pocket I24 which receives a coiled com- 40 pression spring I26 so that the hammer I22 is normally urged toward the firing pin 94. -The.

hammer I22 carries spaced shoulders I28 and I38 which are engaged by a simplified trigger mechanism which will now be described.

A circumferentially narrow, longitudinally extending and radially directed slot I32 is formed in the stock 88 so that the slot runs into commuhication with the bore I28 receiving the hammer I22. A pair of pins I34 is positioned perpendic- 60 ular to the faces of the slot I32 and at equal distances from the bore I28, and these pins, which are carried by the stock 88, are slidably received in a cam slot I35 formed in the flat plate I36 which is extended to form a trigger I38 in prox- 55 imity to the handle portion 82 of the apparatus.

The cam slot I35 in the plate I36 is formed with a downwardly curved end I48 so that when the trigger I38 is pulled the flat plate I36 is moved toward the handle to bring one of the pins I34 v 60 into the curved portion .I48 of the cam slot I35. This tilts the plate I36 away from the axial bore I 28 so that a spring-pressed pawl I42 carried by the plate slides out from engagement behind the collar I38. This causes the hammer.l22 to be driven-forward under the energy stored in the compression spring I26 to thereby strike the firing pin 94 a blow suflicient to overcome the pressure of the spring H2 and detonate the blank cartridge 58. The trigger I38 is now pushed ba k to the full-line position shown in Fig. 2, at which time the spring-pressed pawl I42 rides over the collar I38 to again position the trigger mechanism ready for the pulling and firing operations.

It is believed that the operation of my improved apparatus will be understood from the detailed explanation given above. Suflice it to say here that in accordance with my improved method .and in an operation on a countersunk rivet the rivet to be removed is first center punched, and then the frangible member 42 is aligned with the rivet by positioning the pointed stud 44 in the center punch on the rivet. This aligns the barrel of the apparatus with the rivet, whereupon the trigger I38 is pulled to first move the hammer I22 back to compress the spring I26 with the subsequent release of the hammer to strike the firing pin and detonate the blank cartridge 58. The forward movement of the piston I2 and the punch I4 is retarded by the springpressed detents 68 and by the tapered and wedged fit between the extension 62 on the breech member 58 and the skirt 64 on the piston until substantially the maximum power of the detonated blank cartridge has been realized.

Thereupon, the frictional retarding .means yield to the full pressure of the expanded gases, and the piston I2 and the punch I4 are driven toward the muzzle end of the barrel with tremendous pressure and velocity. The end of the punch I 4 shears the frangible'member 42 and punches through the head of the rivet and into the stem thereof to punch it out of the hole in which it was fixed. I have found that certain rivets yield very easily without absorbing the full force of the piston and punch. The surplus force is absorbed by the shock-absorbing cush ion 28 wherein the rubber'34 is free to flow without tearing. The shock-absorbing unit is also important for the reason that often a rivet may be merely loosened by the first operation of my improved apparatus with a second shot being required. Usually when thisis the case the force required in the second shot is relatively low, and if a standard powder charge is employed a very considerable energy. will have to be absorbed by the shock-absorbing unit 28. Without the use of the shock-absorbing unit there is a metal-tometal impact of the parts which I have found results in considerable breakage of the parts, due to the very high forces created by the detonated explosive charge.

It is believed that the objects of my invention have been achieved by the apparatus and method described. The apparatus is relatively light in weight and can be readilyoperated by the ordinary workman to almost instantly remove a rivet or other headed member from a body substantially without distortion. I'believe that distortion is largely eliminated because of the suddenness of the blow. The apparatus is readily adapted to perform punching operations on rivets of different diameter by merely changing the size of the punch carried bythe piston. This can be accomplished either by removing the retaining nut 22 from the end of the barrel I8 or by removing the barrel I 8 from the breech-member 58, as will be understood. The exhaust gases or any corrosive condensation thereof are bled out from behind the piston to the front of the piston and gradually out to the atmosphere after each operation of the apparatus and relatively simple lubricating means are employed. The breech-block is quickly operable to permit rapid and facile reloading of the apparatus, and the mtiving. It will be appreciated that my imroved method and apparatus are broadly applicable to other punching operations, although they are particularly adapted to operations on rivets or other headed members.

While in accordance with the patent statutes I have specifically illustrated and described one embodiment of my improved apparatus and have given one specific way of practicing my improved method, it will be understood that my invention is not limited thereto or thereby but is defined in the appended claims.

I claim:

1. Apparatus for punching comprising a barrel, a piston slidably mounted in the barrel, a punch carried by the piston, piston-retaining means associated with the muzzle end of the barrel and having an aperture therethrough to permit the passage of the punch, means carried by the retaining means and resiliently cushioning the stopping movement of the piston, a frangible aligning device carried by the retaining means, and means for detonating an explosive charge behind the piston to drive it and the punch towards the muzzle end of the barrel.

2. Apparatus for punching comprising a barrel, a piston slidably mounted in the barrel, a punch carried by the piston, piston-retaining means associated with the muzzle end of the barrel and having an aperture therethrough to permit the passage of the punch, means carried by the retaining means and resiliently cushioning the stopping movement of the piston, said means including a plurality of metal washers surrounding the aperture in the piston-retaining means, a body of rubber vulcanized around the washers but not thereto and holding the washers in spaced relation, integral rubber tabs connecting the layers of rubber between the washers, said body of rubber being of less efiective circumferential area than the washers to provide spaces into which the rubber can be displaced, and means for detonating an explosive charge behind the piston to drive it and the punch towards the muzzle end of the barrel.

3. Apparatus for removing rivets or the like comprising a barrel, 2. piston slidably mounted in the barrel, a punch carried by the piston, pistonretaining means associated with the muzzle end of the barrel and having an aperture therethrough to permit the passage of the punch, a frangible aligning device carried by the retaining means, and means for detonating an explosive charge behind the piston to drive it and the punch towards the muzzle end of the barrel.

4. Apparatus for removing rivets or the like comprising a barrel, a piston slidably mounted in the barrel, a punch carried by the piston, pistonretaining means associated with the muzzle end of the barrel and having an aperture therethrough to permit the passage of the punch, a frangible aligning device carried by the retaining means, said device including a disc adapted to be sheared by the punch and having an outwardly extending pointed stud which is adapted to be placed in a center punch on the work, and means for detonating an explosive charge behind the piston to drive it and the punch towards the muzzle end of the barrel.

5. In explosively actuated apparatus, a barrel, a piston slidably mounted in the barrel, said piston being formed with bleeder vents from its back surface to its cylindrical surface, the barrel being formed with cooperating bleeder vents near its muzzle end, the bleeder vents being adapted to be aligned near the end of the forward movement' of the piston to exhaust the gas behind the piston to the atmosphere, and mea s for detonating an explosive charge behind the piston to drive it towards the muzzle end of the barrel.

6. In explosively actuated apparatus, a barrel, 9. piston slidably mounted in the barrel, said piston and barrel being formed with bleeder vents, the bleeder vents being adapted to be aligned near the end of the forward movement of the piston to exhaust the gas behind the piston to the atmosphere, and means for detonating an explosive charge behind the piston to drive it towards the muzzle end of the barrel.

7. In explosively actuated apparatus, a barrel, a piston slidably mounted in the barrel, a breech member and stock carried by one end of the barrel, a breech-block slidably mounted for limited lateral movement in an aperture in the stock and in one position exposing the breech member for the introduction or removal of an explosive charge and in the other position bringing a firing pin chamber into alignment with the breech member, a firing pin resiliently mounted in the chamber in the breech-block, a hammer slidably carried in the stock remote from the barrel, means for resiliently urging the hammer towards the firing pin, and trigger means for moving the hammer away from the firing pin and for releasing the hammer to detonate the explosive charge.

8. Explosively actuated apparatus comprising a barrel, a member slidably mounted in the barrel, means associated with the end of the barrel and adapted to resiliently stop the movement of the member through the barrel, said means including a plurality of metal plates, a body of rubber vulcanized around the plates but not thereto and serving to hold the plates in spaced relation, integral rubber tabs connecting the layers of rubber between the plates, said body of rubber being of less eifective circumferential area than the metal to provide spaces into which the rubber can be displaced, and means at the other end of the barrel for detonating an explosive charge behind the member to drive it toward the first-named end of the barrel.

9. Explosively actuated apparatus comprising a barrel, 9. member slidably mounted in the barrel, a frangible aligning device carried at the muzzle end of the barrel, said device including a disc-like element having an outwardly extending pointed stud which is adapted to be placed in a center punch on the work, and means for detonating an explosive charge behind the member to drive it toward the muzzle end of the barrel.

ROBERT TEMPLE, J R. 

